pymasep.common.belief

Classes

Belief

The Belief of an agent is all the agent knows about the world and that could have an influence on their actions.

Module Contents

class pymasep.common.belief.Belief(environment, name=None, template=None, xml_node=None, parent=None)

Bases: pymasep.common.BaseObject

The Belief of an agent is all the agent knows about the world and that could have an influence on their actions. Here, the concept of Belief is more inspired by the BDI agent architecture than by the belief of a DEC-POMDP.

Beliefs are based on Conceptual Graphs [Sow84] [CM08]. This version is limited to a simpler version of conceptual graphs. It has been tested with belief of three nodes (concept-relation-concept) See test_belief.py for more details.

NOTE: Contrary to other BaseObjects, src_copy is not used for Belief since Belief instances are never copied but stay as the same reference in the current state

Parameters:

  • environment – An Environment instance

  • name (str) – name of the Belief.

  • xml_node (Optional[xml.etree.ElementTree.Element]) – XML used to create the object.

  • template – Template of the Belief. Needed if no xml_node or src_copy

  • parent – parent object (see objects hierarchy)

beliefs

beliefs data as a conceptual graph

state()

State of the Belief. Always ‘run’

Returns:

The state of Belief

Return type:

str

id_str()

Create an str unique ID of the Belief

Returns:

the string unique ID

Return type:

str

node_id(g, c=None, cr=None)

Get or create the node id of a node in the Belief.

Parameters:

  • g (networkx.Graph) – The graph to create the node id for

  • c (Optional[Tuple[str] | Tuple[str, str]]) – the tuple of attribute of the node id to search if the node already exists

  • cr (Optional[List[Tuple[str, str]]]) – if c is a relation, this parameter represents the concepts linked to the relation

Return type:

int

add(c1, r, c2)

Adding two concepts linked with one relation into the belief

Parameters:

  • c1 (Tuple[str, str]) – First concept as a tuple (concept, instance of the concept)

  • r (Tuple[str]) – relation between concepts.

  • c2 (Tuple[str, str]) – Second concept as a tuple (concept, instance of the concept)

Return type:

None

_create_request(c1, r, c2)
Parameters:

c1 (Tuple[str, str])

query(query)

Query in a Belief

Parameters:

query (networkx.Graph) – Query as a graph. Use * as an instance query.

Return type:

networkx.Graph

Example of a query [Agent:*]-[Tell]-[Sentence:s1] will return a graph containing all agents that tell the sentence s1 in the agent belief.

to_xml()

Transform the Belief to XML. See Serialization for more information.

Returns:

XML version of the BaseObject

Return type:

xml.etree.ElementTree.Element

from_xml(environment, xml_node)

Transform an XML to a Belief. The instance must be created before (with __init__(), passing the xml_node). See Serialization for more information.

Parameters:

  • environment – The environment where the BaseObject is created.

  • xml_node (xml.etree.ElementTree.Element) – The XML node that contains the Belief data.